If the ViewSonic's touch capability in Extended Desktop mode is "off" you need to fix the setting in Windows.  To fix those settings do the following:

1. Click on the Windows Charm on the bottom left and type "Control Panel" in the search then click on Control Panel in the list that appears.
2. Then tap or click Hardware and Sound. The Hardware and Sound menu displays.
3. Then tap or click on Calibrate the screen for pen or touch input under Tablet PC Settings.
4. In the window that appears choose the ViewSonic (should say IFP7550) from the "Display" drop-down menu
5. Click on the Setup button.
   NOTE: this process must be done with administrative privileges so if you are logged into the desktop as a teacher you will need to enter the password for the local admin account when you click on the Setup button. 
6. The computer monitor will display a message to "tap the screen if it is the display to calibrate or hit enter to go to the next screen".
7. Hit Enter.
8. The same message will appear on the IFP.
9. Tap the screen on the IFP.
10. The screen will go back to normal and you can then close the Control Panel.
11. Now when you set the PC to "Extended Desktop" the touch orientation will be accurate.

Windows 10 - https://www.windowscentral.com/how-calibrate-touch-enabled-display-windows-10